In the tree pruning and removal industry, it has generally become standard operating procedure to chip the wood and brush debris generated during normal tree pruning or removal operations. The process of chipping limbs reduces bulky branches into a form more suitable to dense packing. The chipping of branches and brush into small chips allows for more material to be stored in a single container, therefore reducing the number of trips an individual must make to a storage or dumping location.
Prior art chippers are predominantly trailerized with axles, wheels and hitches for towing behind a truck equipped with what is commonly termed a “chipper dump box” (often referred to as a “dump box”). Chipper dump boxes are basically large boxes typically made of wood or steel that have been designed to catch and contain wood chips as they are thrown from the exit chute of a trailerized wood chipper towed behind the truck. To unload, gates are opened and the contents of the box are dumped, hence the name “chipper dump box”. Chipper dump boxes have some type of roof or tarp covering on the top to prevent the woodchips from blowing out over the top of the chipper dump box because the chips exit the chipper with considerable velocity. The gate or gates of the chipper dump box are to the rear of the box (immediately in front of the towed chipper) and are short enough to allow the chipper to shoot the wood chips over the top of the gate or gates and into the chipper dump box. With this configuration, the truck can be large and the chipper dump box can subsequently be manufactured to have a quite large capacity for chips.
The chipper dump box hinges near the rear of the truck, and after the gates are swung open, the front of the chipper dump box is raised and the chips are dumped out the rear of the chipper dump box. But, before the filled chipper dump box can be dumped, the trailerized chipper must first be unhitched from the truck and left where it sits, or the truck's load of wood chips would be dumped on top of the chipper.
This standard setup adds unnecessary complexity and time to the procedure of dumping the load because not only must the chipper be unhooked from the truck (hereafter called “chipper truck”) prior to dumping its load, the chipper must also be backed up to and reconnected (hitch, safety chains, electrical for lights and mandatory “breakaway” brake activator) to the chipper truck before traveling to the next job site. With the basic chipper truck pulling the basic chipper, there is no aerial lift device (with a basket at the end of the boom for an operator to most efficiently access trees) for performance of general tree pruning or removal work.
However, chipper trucks often do include an aerial lift unit (with a basket for an operator at the end of the boom) for a man to work out of so as to be able to most efficiently prune tree branches high above the ground. With an aerial lift included, the chipper dump box must be mounted at the rear of the truck, and the pedestal of the aerial lift unit must be mounted in front of the chipper dump box, immediately behind the cab of the truck (as opposed to the pedestal of the aerial lift being mounted at the rear of the truck). This configuration not only severely limits the size of the chipper dump box, (because the aerial lift's folded boom must rest directly on top of the chipper dump box in a cradle) but the necessary location of the pedestal of the aerial lift device compromises the usefulness of the aerial lift. This is because the forward location of the pedestal (immediately behind the cab) lessens the operator's ability to reach up and out to the rear of the truck, so that not only is overall reach capability generally compromised, (because the pedestal's location in the east-west “middle” of the truck, as opposed to quite close to the end of the truck with a rear mounted pedestal), but that the bulk of tree pruning and removal work has to be done to the vulnerable front and sides of the truck. As more caution must be used (cutting and felling heavy limbs and logs adjacent to the trucks chip dump box and cab), the time required to perform the work increases. With this configuration, when preparing to dump the chipper dump box, (in addition to dropping off the chipper) the operator must first raise the boom of the aerial lift unit before the dump box can be raised. The process having to be repeated in reverse after dumping the load. It should also be noted that weight carrying requirements of such a truck are so large, the bed of the chip box is necessarily quite high off the ground (due to the large frame, wheels, tires, springs and axles under the truck) making it extremely difficult to manually lift and throw logs of any size into the back of the dump box.
The fold position aerial lift above the dump box also must meet height restrictions so that the truck can safely pass beneath bridges, overhead wires, and other structures. Therefore, the height of the dump box must be reduced to accommodate the aerial lift, which reduces the capacity of the dump box.
Aerial lift trucks with chipper dump boxes also have weight considerations. Preferably, the gross weight must be less than 26,000 pounds, so that the driver does not need a commercial driver's license. Based on typical truck and aerial lift weights, the load in the dump box cannot exceed approximately 5,000 pounds, thus further limiting the size and capacity of the box.
Electric utility companies often sub-contract tree services to prune trees clear from their high voltage power lines, but other companies do the work themselves. Generally, when electric utility companies do their own line clearance work, they use their existing fleet of aerial lift units designed for the electric utility industry. These trucks are equipped with “utility bodies” (large cabinets of tool boxes mounted on each side of the truck for the large number of parts and tools required in the industry) and the pedestals of the aerial lift units are mounted at the rear of the truck over the drive axle. As there can physically be no chipper dump box on these trucks, these utility companies must find other means for cleaning up the wood and brush debris generated from the pruning or removal of the trees. This typically means that they must also bring a chipper truck pulling a wood chipper behind it to the job site, thus increasing costs with two vehicles, two drivers, as well as dual registrations, insurance, double the fuel consumption and maintenance.
Another prior art wood chipper, sold by Bandit Industries under the trademark Brush Bandit, is mounted on the front of a trailer, on part of the trailer tongue. This chipper can be rotated toward the passenger side or the driver side. There is a chipper dump box mounted to the rear of the chipper over the axles. The configuration precludes backing up to access multiple piles of brush staged in a line, (such as up a driveway, between houses, between hedges, in an alley, etc.), which is a significant impediment to the brush chipping process. Also, because the Bandit chipper shoots the chips to the rear of the chip box (the box dumps to the rear), the chips immediately pile up high against the gate, meaning that logs or slash cannot be thrown into the chip box after almost any amount of chipping has been done. The Bandit rear gate is not designed to enable rear loading access. Additionally, not only is the size of the chipper negatively limited, due to its location on the tongue, but the box is logically made to match the smaller size of the chipper and there is subsequently no open roof to allow for the craning of large logs into the box.